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Re:STM32 Open Source Multimeter by elvecinodeabajo on Thursday June 20, 2019 @10:09PM (#20239278)
The safety! Safety is the most important part in my opinion.

I've bought a DSO138 DIY Oscilloscope Kit clone in eBay and I'm scared to connect it to 220V main line because I've not reliable information or safety warranties (It's a clone, not the DYE Tech certified one).

Not everybody cares about safety as they should.

Re:STM32 Open Source Multimeter by semi-extrinsic on Friday June 21, 2019 @02:15AM (#20240268)
Hmm? I don't get this.

If you're talking about the power adapter, you can buy a reputable one (it's external to the scope).

If you're talking about measurements on 220V equipment, just buy a genuine Digilent (or other brand) probe with 10x attenuation for about $20, then you can have complete faith in that the scope electronics will only see signals < 48V, which is completely safe.

Re:STM32 Open Source Multimeter by elvecinodeabajo on Friday June 21, 2019 @07:55AM (#20241650)
My bad! I was a bit drunk when posted that. I was talking about viewing the sine AC wave in the scope. Didn't try yet but I expect a funny smelly 'poof' and mainline fuses pop up. Probably my curiosity will finish blowing everything up just for confirmation. lol

You talk like you trust quite much in Digilent. I'll keep it in mind when looking for some instrumentation. Thanks a lot!

Re:STM32 Open Source Multimeter by marcosdumay on Friday June 21, 2019 @01:19PM (#20244519)
Well, you do what I do with any electronics I create, place it on some ventilated area where fire can't spread, have long cables with switches far from the equipment, do any work with power off (after waiting for any capacitor discharge), and wait for the "tshhhhh" every so often.

After it is well tested (measuring temperatures is hard, but doable) and you are confident it works, you can use it normally.

Re:STM32 Open Source Multimeter by semi-extrinsic on Friday June 21, 2019 @08:49AM (#20242022)
No worries. Looking at the sine AC wave should be fine. If you get a "10X" probe or one that has a 1X/10X switch, what happens in 10X mode is that the voltage gets divided by 10 through a resistor, so your multimeter should see 22V RMS sine wave (peak value should be 31V).
Re:STM32 Open Source Multimeter by atoav on Friday June 21, 2019 @05:52AM (#20241163)
We lived with quite safe electronics for quite a while so many don't even think about safety. If you experienced 230V AC through your body, you will think quite differently.
Re:STM32 Open Source Multimeter by TeMPOraL on Friday June 21, 2019 @07:49AM (#20241620)
This is literally what currently prevents me from doing DIY IoT projects at home. I'm not proficient enough in hardware to build battery-powered items, and I'm scared of leaving unattended anything I built that's powered off a wall wart.
Re:STM32 Open Source Multimeter by elvecinodeabajo on Friday June 21, 2019 @08:04AM (#20241701)
To loss the fear just experiment with some safety and take measurments. You can let plugged a new project during some hours to look if it makes nasty things or not.

Anyway, I really encourage you to doing DIY projects at home. Most of them work in low voltages between 5 and 3.3V, risks are close to nothing.

Re:STM32 Open Source Multimeter by kragen on Thursday June 20, 2019 @10:21PM (#20239325)
You start caring after a couple of good 120VAC jolts through your torso. You'll probably survive that if it isn't too hot that day, and you don't get unlucky and grab the line. 220VAC, though, better not learn the hard way

Che, no te importa si cuelgo de tu wifi, o sí?

Re:STM32 Open Source Multimeter by elvecinodeabajo on Friday June 21, 2019 @07:59AM (#20241670)
Didn't feel 120V, but 220V is a weird experience. It's not the spiky puncture of a car's spark plug, it's like a scary wave flowing through you. As cool as deadly. (Kids, don't try at home!)

Oiga! Yo le subo wifi, usted baje unas chelas fresquitas! :p

Re:STM32 Open Source Multimeter by patrick5415 on Sunday June 23, 2019 @12:26AM (#20253303)
I’ve been buzzed by 120 quite a few times. Never 220 though. I also got shocked by about 800 volts from a tube radio once, which lit me up pretty good. Fortunately that was pretty low amperage I think.